Method and device for amplifying sensitivity of interference type optical fiber sensor

Abstract

The invention discloses a method and device for amplifying the sensitivity of an interference type optical fiber sensor, and relates to the technical field of optical fiber sensing, and the method comprises the steps: collecting original broadband light source spectral data, constructing an artificial spectral data set based on the original broadband light source spectral data and a virtual spectral data set, the method comprises the following steps: acquiring measured spectral data of an interference type optical fiber sensor in a to-be-measured environment in real time, selecting reference spectral data according to a preset target magnification factor, subtracting through a spectrograph channel to obtain a vernier effect spectral data set, performing upper envelope fitting operation on each piece of vernier effect spectral data, recording a wavelength value corresponding to a feature tracking point, and calculating the spectral data of the interference type optical fiber sensor according to the wavelength value. And obtaining a predicted value of the physical quantity to be measured based on demodulation of the wavelength value-physical quantity parameter table. According to the virtual spectrum data set generating and processing method, the sensitivity of the interference type optical fiber sensor is remarkably improved, the system structure is simplified, the cost is reduced, and the stability and reliability of the system are improved.

Description

Technical Field

[0001] This application relates to the field of fiber optic sensing technology, and in particular to a method and apparatus for amplifying the sensitivity of an interferometric fiber optic sensor. Background Technology

[0002] With the rapid development of modern industry and scientific research, the demand for high-precision, high-sensitivity sensors is increasing daily. Fiber optic sensors, due to their unique advantages such as strong resistance to electromagnetic interference, small size, light weight, and remote monitoring capabilities, have been widely used in numerous fields. Interferometric fiber optic sensors, as an important branch of fiber optic sensors, measure various physical quantities, such as temperature, strain, and pressure, by detecting changes in the interference pattern of light.

[0003] However, interferometric fiber optic sensors have certain limitations in terms of sensitivity. To improve measurement sensitivity, the fiber optic vernier effect technique is commonly used. This technique generates a vernier effect spectrum by superimposing the spectra of two interferometers, thereby amplifying the sensitivity. However, the vernier effect excitation method in this technique requires the integration of two physical sensors, which not only increases the complexity and cost of the system but also faces the challenge of matching core parameters, leading to a decrease in the success rate of vernier spectrum generation, deviations in the actual amplification, and a significant decrease in system calibration efficiency. Furthermore, while the Vernier fast matching technique based on virtual spectra can theoretically improve sensitivity, the actual measurement limit is still determined by a single interferometer because the data it uses is essentially the sensitivity of a single spectrum, limiting its value in practical applications.

[0004] Therefore, there is an urgent need for an interferometric fiber optic sensor sensitivity amplification method to solve the problems of high system complexity, high cost, difficulty in matching core parameters, and lack of effective improvement in measurement limits in existing technologies. Summary of the Invention

[0005] The purpose of this application is to provide a method and apparatus for amplifying the sensitivity of an interferometric fiber optic sensor, which can solve the problems of high system complexity, high cost, difficulty in matching core parameters, and lack of effective improvement in measurement limits in the prior art, thereby improving the sensitivity and measurement accuracy of the interferometric fiber optic sensor, simplifying the system structure, reducing costs, and improving the stability and reliability of the system.

[0006] To achieve the above objectives, this application provides the following solution:

[0007] In a first aspect, this application provides a method for amplifying the sensitivity of an interferometric fiber optic sensor, comprising:

[0008] Acquire raw broadband light source spectral data;

[0009] Based on the original broadband light source spectral data and the virtual spectral data set, an artificial spectral data set is constructed; the virtual spectral data set is generated by different virtual cavity length parameters in the Fabry-Perot interferometer sensor according to the reflection spectrum calculation formula of the Fabry-Perot interferometer sensor.

[0010] The measurement spectral data of the broadband light source under the test environment is acquired in real time through the interferometric fiber optic sensor to obtain the measurement spectral data set, and the measurement spectral data set is stored in channel A of the spectrometer;

[0011] Based on the preset target magnification and the free spectral range of the interferometric sensor, the corresponding artificial spectral data is selected from the artificial spectral data group and stored as reference spectral data in channel B of the spectrometer, and channel B of the spectrometer is fixed.

[0012] Subtract each measured spectral data point in channel A of the spectrometer from the reference spectral data in channel B of the spectrometer to obtain the vernier effect spectral data point, and store it in channel C of the spectrometer.

[0013] For each vernier effect spectral data in channel C of the spectrometer, an upper envelope fitting operation is performed to obtain multiple envelope curves;

[0014] The peak point of each envelope curve is used as the feature tracking point, and the wavelength value corresponding to each feature tracking point is recorded.

[0015] Based on the preset wavelength value-physical quantity parameter table, the wavelength values ​​of each feature tracking point are demodulated to obtain the predicted value of the physical quantity to be measured in the environment under test within the prediction time period, thereby realizing the function of sensitivity amplification; the physical quantity to be measured is the target detection physical quantity of the original interferometric sensor, including temperature and strain.

[0016] Secondly, this application provides a device for amplifying the sensitivity of an interferometric fiber optic sensor, comprising:

[0017] Broadband light source, circulator, spectrometer, interferometric fiber optic sensor, multiple transmission fibers;

[0018] The first port of the circulator is connected to a broadband light source via a transmission optical fiber, the second port of the circulator is connected to an interferometric fiber optic sensor via a transmission optical fiber, and the third port of the circulator is connected to the input end of a spectrometer via a transmission optical fiber.

[0019] The broadband light source is used to transmit optical signals to the interferometric fiber optic sensor;

[0020] The interferometric fiber optic sensor is used to receive the light signal emitted by the broadband light source and reflect it to obtain the measurement spectral data of the interferometric fiber optic sensor under the test environment, and transmit the measurement spectral data to the spectrometer.

[0021] The spectrometer has data acquisition channels including channel A, channel B, and channel C. It is used to select corresponding artificial spectral data from the artificial spectral data set according to a preset target magnification, store this as reference spectral data in channel B of the spectrometer, and fix channel B. Each measured spectral data in the measured spectral data set in channel A of the spectrometer is subtracted from the reference spectral data in channel B to obtain a vernier effect spectral data set, which is then stored in channel C. An upper envelope fitting operation is performed on each vernier effect spectral data in the vernier effect spectral data set in channel C of the spectrometer to obtain multiple envelope curves. The peak point of each envelope curve is used as a feature tracking point, and the wavelength value corresponding to each feature tracking point is recorded. Based on a preset wavelength value-physical quantity parameter table, the wavelength value of each feature tracking point is demodulated to obtain the predicted value of the measured physical quantity in the environment under test within the prediction time period, thus achieving the function of sensitivity amplification. The measured physical quantity is the target physical quantity detected by the original interferometric sensor, including temperature, strain, etc.

[0022] Thirdly, this application provides a computer device, including: a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the computer program to implement the steps of the method for amplifying the sensitivity of the interferometric fiber optic sensor as described above.

[0023] Fourthly, this application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the method for amplifying the sensitivity of the interferometric fiber optic sensor described above.

[0024] Fifthly, this application provides a computer program product, including a computer program that, when executed by a processor, implements the steps of the method for amplifying the sensitivity of the interferometric fiber optic sensor described above.

[0025] According to the specific embodiments provided in this application, this application has the following technical effects:

[0026] This application provides a method and apparatus for amplifying the sensitivity of an interferometric fiber optic sensor. By acquiring raw broadband light source spectral data and constructing an artificial spectral data set based on this data and a virtual spectral data set, it solves the problems of high system complexity and high cost caused by the need for dual physical sensors in the prior art, and achieves a significant improvement in sensitivity. By acquiring the measurement spectral data of the interferometric fiber optic sensor in the test environment in real time and subtracting it from the artificial spectral data to obtain the vernier effect spectral data set, it solves the core parameter matching problem and improves the success rate of vernier spectrum generation and the accuracy of actual amplification. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is an application environment diagram of a method for amplifying the sensitivity of an interferometric fiber optic sensor according to an embodiment of this application;

[0029] Figure 2 A flowchart illustrating a method for amplifying the sensitivity of an interferometric fiber optic sensor, provided in an embodiment of this application;

[0030] Figure 3 A functional module diagram of an amplification device for the sensitivity of an interferometric fiber optic sensor provided in an embodiment of this application; wherein, Figure 3 (a) is a schematic diagram of the structure and connection of the amplification device for the sensitivity of the interferometric fiber optic sensor; Figure 3 (b) is a schematic diagram of an interferometric fiber optic sensor; Figure 3 (c) is a physical image of an interferometric fiber optic sensor;

[0031] Figure 4 A flowchart illustrating a method for amplifying the sensitivity of an interferometric fiber optic sensor, provided as another embodiment of this application;

[0032] Figure 5 This is a schematic diagram of raw spectral data and artificial spectral data provided in an embodiment of this application; wherein, Figure 5 (a) is a schematic diagram of the original spectrum of the broadband light source; Figure 5 (b) is a schematic diagram of an artificial spectrum with a virtual cavity length parameter of 10 μm; Figure 5 (c) is a schematic diagram of an artificial spectrum with a virtual cavity length parameter of 105 μm; Figure 5 (d) is a schematic diagram of an artificial spectrum with a virtual cavity length parameter of 400 μm;

[0033] Figure 6 This is a schematic diagram of vernier effect spectral data provided in an embodiment of this application;

[0034] Figure 7 A schematic diagram illustrating the predicted values ​​of strain physical quantities provided in an embodiment of this application;

[0035] Figure 8 This is a schematic diagram of the structure of a computer device provided in an embodiment of this application.

[0036] Figure reference numerals: 1-Broadband light source, 2-Circulator, 3-Interferometric fiber optic sensor, 4-Spectrometer, 5-Transmission fiber, S1-First port of the circulator, S2-Second port of the circulator, S3-Third port of the circulator, M1-Reflective surface formed by the first end face of the single-mode fiber and air, M2-Reflective surface formed by the second end face of the single-mode fiber and air. Detailed Implementation

[0037] First, some technical terms involved in the embodiments of this application will be introduced.

[0038] Fiber optic interferometric fiber optic sensor (IFOS): This type of fiber optic sensor uses multiple beams of light in an optical fiber to generate multiple orders of interference fringes for measurement. Based on the type of interference, it can be mainly divided into: Mach-Zehnder interferometer (MZI), Michelson interferometer, Sagnac interferometer, Fabry-Pérot interferometer (FPI), etc.

[0039] Fabry-Perot interferometer (FPI): An optical interference structure consisting of two parallel glass plates, which can be used for filtering, sensing, etc.

[0040] Traditional Vernier Effect (TVF): The TVF effect is a method to enhance the sensitivity of interferometric sensors based on the interference mechanism. This effect is suitable for enhancing the sensitivity of interferometers: by superimposing the spectra of two interferometers (adding or multiplying spectral terms), a vernier effect spectrum is formed. The envelope of the vernier effect spectrum has a sensitivity amplification effect compared to the original spectrum, i.e., the fiber optic vernier effect. It is produced by combining two interference structures with similar interference frequencies to generate a least common multiple periodic spectrum, which can effectively improve sensitivity.

[0041] Sensing FPI (SFPI): The FPI used in the sensing part of a vernier effect sensor, which is sensitive to the parameter to be measured.

[0042] Reference FPI (RFPI): An FPI used in vernier effect sensors to provide a stable reference spectral portion. It is insensitive to the parameter being measured or is placed in an environment other than the one being measured.

[0043] Free spectr μmrange (FSR): This refers to the free spectral range, and can also represent the period of a periodic spectrum.

[0044] Effective optical path length: refractive index multiplied by physical length.

[0045] The vernieffect (VF) is a method to enhance the measurement sensitivity of interferometric fiber optic sensors based on the interferometric mechanism. This effect is applicable to the enhancement of interferometer sensitivity: the spectra of two interferometers are superimposed (spectral terms are added or multiplied) to form a vernieffect spectrum. The envelope of the vernieffect spectrum has a sensitivity amplification effect compared to the original spectrum. Similar to vernier calipers, the spectral periods of the two interferometers in a vernieffect sensor are close, but not exactly the same. One interferometer provides only a reference spectrum, while the other provides the sensing spectrum, and both are placed in the environment to be measured for sensing. Existing methods for activating the vernieffect mainly utilize the combination of two fabricated interferometric sensors (these two interferometric sensors can be the same or different), such as: Fabry-Perot (FP) combination, Mach-Zehnder (MZ) combination, Sagnac combination, and combinations of multiple interferometers.

[0046] The following problems exist in the current related technologies:

[0047] System complexity and cost are issues. Related technologies require the integration of dual physical sensors in the sensing system, necessitating the introduction of additional optical components such as fiber optic couplers and multiple circulators, resulting in a complex system structure and high hardware costs. This multi-component architecture not only increases assembly difficulty but also significantly raises the overall cost.

[0048] Current vernier effect-based sensing systems face a core parameter matching challenge: to generate an effective fiber optic vernier effect, the free spectral range (FSR) of the two interferometers must be highly similar but not identical. Taking a fiber optic FPI sensor as an example, the sensitivity amplification is positively correlated with the optical path matching accuracy of the sensing FPI (SFPI) / reference FPI (RFPI). However, current fabrication processes (including but not limited to mechanical cutting, fusion splicing, heterogeneous fiber splicing, and laser micromachining) have inherent tolerances, causing the actual optical path difference between the SFPI and RFPI to deviate from the design value, ultimately leading to three major problems: reduced vernier spectrum generation success rate, deviation in actual amplification, and a significant decrease in system calibration efficiency.

[0049] The Vernier rapid matching technique based on virtual spectroscopy in related technologies suffers from the problem of not improving the measurement limit. This Vernier effect sensor based on virtual spectroscopy acquires the spectrum of a single interferometric sensor, then exports this measured spectral data to a spectrometer and adds a simulated spectrum, thereby amplifying the Vernier effect sensitivity. However, since the data used is essentially the sensitivity of a single spectrum, the actual measurement limit is still determined by a single FPI. Therefore, the Vernier rapid matching technique based on virtual spectroscopy has limited practical application value.

[0050] In summary, this application proposes a method for amplifying the sensitivity of an interferometric fiber optic sensor, which can achieve rapid vernier effect matching of a single interferometric sensor and reduce the difficulty of traditional Vernier effect matching.

[0051] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0052] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0053] The method for amplifying the sensitivity of the interferometric fiber optic sensor provided in this application embodiment can be applied to, for example... Figure 1In the application environment shown, terminal 101 communicates with server 102 via a network. A data storage system can store the data that server 102 needs to process. The data storage system can be set up separately, integrated into server 102, or placed in the cloud or on another server. Terminal 101 can send the raw spectral data of the broadband light source and the measured spectral data of the interferometric fiber optic sensor in the test environment to server 102. After receiving the raw spectral data of the broadband light source and the measured spectral data of the interferometric fiber optic sensor in the test environment, server 102 constructs an artificial spectral data set based on the raw broadband light source spectral data and the virtual spectral data set. The virtual spectral data set is generated according to the reflection spectrum calculation formula of the Fabry-Perot interferometer sensor, using different virtual cavity length parameters in the Fabry-Perot interferometer sensor. The measured spectral data of the broadband light source passing through the interferometric fiber optic sensor in the test environment is collected in real time to obtain the measured spectral data set, which is then stored in channel A of the spectrometer. Based on the preset target magnification and the free spectral range of the interferometric sensor, the artificial light... The corresponding artificial spectral data is selected from the spectral data set and stored as reference spectral data in channel B of the spectrometer, and channel B of the spectrometer is fixed. Each measured spectral data in the measured spectral data set in channel A of the spectrometer is subtracted from the reference spectral data in channel B of the spectrometer to obtain the vernier effect spectral data set, which is then stored in channel C of the spectrometer. An upper envelope fitting operation is performed on each vernier effect spectral data in the vernier effect spectral data set in channel C of the spectrometer to obtain multiple envelope curves. The peak point of each envelope curve is used as a feature tracking point, and the wavelength value corresponding to each feature tracking point is recorded. Based on a preset wavelength value-physical quantity parameter table, the wavelength value of each feature tracking point is demodulated to obtain the predicted value of the measured physical quantity in the environment under test within the prediction time period, thus realizing the sensitivity amplification function. The measured physical quantity is the target physical quantity detected by the original interferometric sensor, including temperature and strain. The server 102 can feed back the obtained predicted values ​​of each measured physical quantity in the environment under test to the terminal 101. Furthermore, in some embodiments, the method for amplifying the sensitivity of the interferometric fiber optic sensor can also be implemented separately by the server 102 or the terminal 101. For example, the terminal 101 can directly perform predictive processing on the original spectral data of the broadband light source and the measured spectral data of the interferometric fiber optic sensor in the test environment. Alternatively, the server 102 can obtain the original spectral data of the broadband light source and the measured spectral data of the interferometric fiber optic sensor in the test environment from the data storage system, and perform predictive processing on the original spectral data of the broadband light source and the measured spectral data of the interferometric fiber optic sensor in the test environment.

[0054] The terminal 101 can be, but is not limited to, various desktop computers, laptops, smartphones, tablets, IoT devices, and portable wearable devices. The server 102 can be implemented using a standalone server or a server cluster consisting of multiple servers, or it can be a cloud server.

[0055] In one exemplary embodiment, such as Figure 2 As shown, a method for amplifying the sensitivity of an interferometric fiber optic sensor is provided. This method is executed by a computer device, specifically by a terminal or server alone, or by both a terminal and a server. In this embodiment, the method is applied to... Figure 1 Taking server 102 as an example, the explanation includes the following steps 201 to 208.

[0056] in:

[0057] Step 201: Collect raw broadband light source spectral data.

[0058] Step 202: Based on the original broadband light source spectral data and the virtual spectral data set, construct an artificial spectral data set; the virtual spectral data set is generated by different virtual cavity length parameters in the Fabry-Perot interferometer sensor according to the reflection spectrum calculation formula of the Fabry-Perot interferometer sensor.

[0059] Step 203: Real-time acquisition of the measurement spectral data of the broadband light source through the interferometric fiber optic sensor in the test environment, obtaining the measurement spectral data set, and storing the measurement spectral data set into channel A of the spectrometer.

[0060] Step 204: Based on the preset target magnification and the free spectral range of the interferometric sensor, select the corresponding artificial spectral data from the artificial spectral data group, store it as reference spectral data in channel B of the spectrometer, and fix channel B of the spectrometer.

[0061] Step 205: Subtract each measured spectral data in the measured spectral data set in channel A of the spectrometer from the reference spectral data in channel B of the spectrometer to obtain the vernier effect spectral data set, and store it in channel C of the spectrometer.

[0062] Step 206: Perform upper envelope fitting operation on each vernier effect spectral data in the vernier effect spectral data group in channel C of the spectrometer to obtain multiple envelope curves.

[0063] Step 207: Take the peak point of each envelope curve as the feature tracking point and record the wavelength value corresponding to each feature tracking point.

[0064] Step 208: Based on the preset wavelength value-physical quantity parameter table, demodulate the wavelength values ​​of each feature tracking point to obtain the predicted value of the physical quantity to be measured in the environment under test within the prediction time period, thereby realizing the function of sensitivity amplification; the physical quantity to be measured is the target detection physical quantity of the original interferometric sensor, including temperature and strain.

[0065] By implementing steps 201 to 208 above, this application can directly generate the vernier effect in the spectrometer using a virtual cavity long sequence, thereby increasing the sensitivity of a single interferometer by a preset factor, while eliminating the need for a physical reference cavity and reducing system complexity and cost.

[0066] In another exemplary embodiment of this application, the virtual spectral data set in step 202 is generated based on the Fabry-Perot interferometer sensor reflectance spectrum calculation formula, using different virtual cavity length parameters in the Fabry-Perot interferometer sensor, specifically including:

[0067] The following formulas are used to obtain multiple virtual cavity length parameters:

[0068] L i =L0+i×ΔL.

[0069] Among them, L i Let L0 represent the i-th virtual cavity length parameter, i = {1, 2, 3, ..., I}, where I represents the total number of virtual cavity lengths; L0 represents the initial cavity length parameter; and ΔL represents the preset cavity length interval.

[0070] The virtual reflection spectrum corresponding to each virtual cavity length parameter is calculated using the following formula:

[0071]

[0072] Among them, P i (λ) represents the virtual reflection spectrum corresponding to the i-th virtual cavity length parameter; E r,i E represents the amplitude of the reflected electric field for the i-th virtual cavity length parameter; in,i R1 represents the incident electric field amplitude of the i-th virtual cavity length parameter; R2 represents the reflectivity of the first end face of the Fabry-Perot interferometer sensor; α represents the transmission loss coefficient; n′ represents the virtual refractive index corresponding to the virtual spectrum; and λ represents the wavelength of the incident light.

[0073] Based on each virtual cavity length parameter and the corresponding virtual reflection spectrum, a virtual spectral data set is obtained.

[0074] In another exemplary embodiment of this application, step 202 specifically includes:

[0075] The original broadband light source spectral data is subjected to an exponential operation with a base of 10 using the following formula. The exponentially operated original broadband light source spectral data is then multiplied by each virtual spectral data in the virtual spectral data set to obtain the intermediate spectral data set.

[0076] O i =(10 O(λ) *P i (λ)).

[0077] Among them, O i O(λ) represents the intermediate spectral data corresponding to the i-th virtual cavity length parameter; O(λ) represents the original broadband light source spectral data; P i (λ) represents the virtual reflection spectrum corresponding to the i-th virtual cavity length parameter.

[0078] The artificial spectral data set is obtained by taking the logarithm of each intermediate spectral data set using the following formula.

[0079] A i (λ)=lg(10 O(λ) *P i (λ)).

[0080] Among them, A i (λ) represents the artificial spectral data corresponding to the i-th virtual cavity length parameter.

[0081] In another exemplary embodiment of this application, step 204 specifically includes:

[0082] Based on the preset target magnification and the free spectral range of the acquired interferometric fiber optic sensor, the corresponding target virtual cavity length parameter L is obtained using the vernier effect sensitivity amplification formula. x ;

[0083] Based on the corresponding target virtual cavity length parameter L x The target virtual cavity length parameter L is calculated using a preset numbering formula. x The corresponding artificial spectral data number x to be selected;

[0084] Based on the artificial spectral data number x to be selected, the corresponding artificial spectral data is selected from the artificial spectral data group.

[0085] In another exemplary embodiment of this application, the vernier effect sensitivity is expressed as follows:

[0086]

[0087] Where m represents the preset target magnification; FSR1 and FSR2 are the free spectral ranges of the acquired interferometric sensor and the selected artificial spectrum, respectively; n′=1, representing the virtual refractive index corresponding to the virtual spectrum; L x This represents the target virtual cavity length parameter; all units in the above formulas are in μm.

[0088] The default numbering formula is:

[0089] n′L x =10+(x-1)*0.5μm.

[0090] Where x represents the sequence number of the artificial spectral data to be selected, x∈{1,2,3,.....,I}.

[0091] In another exemplary embodiment of this application, the virtual cavity length parameter varies in the range of 10μm-400μm; the preset cavity length interval is 0.5μm.

[0092] This application also provides an application scenario in which the above-described method for amplifying the sensitivity of an interferometric fiber optic sensor is applied. Specifically, the method for amplifying the sensitivity of an interferometric fiber optic sensor provided in this embodiment can be applied to the safety monitoring scenario of subsea oil and gas pipelines. The safety monitoring scenario of subsea oil and gas pipelines includes pipeline laying, real-time monitoring, data processing, and risk warning. The sensing fiber optic cable enters the seabed during pipeline laying, collects temperature and strain data in real time, and completes vernier amplification and demodulation through a circulator, spectrometer, and server to obtain high-precision leak or deformation prediction values, which are then sent to the risk warning platform. The method for amplifying the sensitivity of an interferometric fiber optic sensor provided in this embodiment is a core algorithm in the data processing stage. It improves sensitivity by using a software virtual cavity length, achieving centimeter-level leak location and millisecond-level response in the deep-sea environment without the need for an additional physical reference cavity.

[0093] Based on the same inventive concept, this application also provides an apparatus for amplifying the sensitivity of an interferometric fiber optic sensor to implement the aforementioned method for amplifying the sensitivity of an interferometric fiber optic sensor. The solution provided by this apparatus is similar to the solution described in the above method. Therefore, the specific limitations in one or more embodiments of the apparatus for amplifying the sensitivity of an interferometric fiber optic sensor provided below can be found in the limitations of the method for amplifying the sensitivity of an interferometric fiber optic sensor described above, and will not be repeated here.

[0094] In one exemplary embodiment, such as Figure 3 As shown, a sensitivity amplification device for an interferometric fiber optic sensor is provided, comprising:

[0095] 1. Broadband light source; 2. Circulator; 4. Spectrometer; 3. Interferometric fiber optic sensor; 5. Multiple transmission fibers;

[0096] The first port S1 of the circulator 2 is connected to the broadband light source 1 through the transmission optical fiber 5, the second port S2 of the circulator 2 is connected to the interferometric fiber optic sensor 3 through the transmission optical fiber 5, and the third port S3 of the circulator 2 is connected to the input end of the spectrometer 4 through the transmission optical fiber 5.

[0097] The broadband light source 1 is used to transmit optical signals to the interferometric fiber optic sensor 3;

[0098] The interferometric fiber optic sensor 3 is used to receive the light signal emitted by the broadband light source 1 and reflect it to obtain the measurement spectral data of the interferometric fiber optic sensor 3 under the test environment, and transmit the measurement spectral data to the spectrometer 4.

[0099] The spectrometer 4 has data acquisition channels including channel A, channel B, and channel C. It is used to select corresponding artificial spectral data from the artificial spectral data set according to a preset target magnification, store this as reference spectral data in channel B of the spectrometer, and fix channel B. Each measured spectral data in the measured spectral data set in channel A of the spectrometer is subtracted from the reference spectral data in channel B of the spectrometer to obtain a vernier effect spectral data set, which is then stored in channel C of the spectrometer. An upper envelope fitting operation is performed on each vernier effect spectral data in the vernier effect spectral data set in channel C of the spectrometer to obtain multiple envelope curves. The peak point of each envelope curve is used as a feature tracking point, and the wavelength value corresponding to each feature tracking point is recorded. Based on a preset wavelength value-physical quantity parameter table, the wavelength value of each feature tracking point is demodulated to obtain the predicted value of the measured physical quantity in the environment under test within the prediction time period, thus realizing the sensitivity amplification function. The measured physical quantity is the target physical quantity detected by the original interferometric sensor, including temperature, strain, etc.

[0100] The following example illustrates this application using the amplification process of a specific interferometric fiber optic sensor sensitivity.

[0101] like Figure 3 The diagram shows a functional module schematic of an interferometric fiber optic sensor sensitivity amplification device. The device comprises a broadband light source 1, a circulator 2, a spectrometer 4, an interferometric fiber optic sensor 3, and multiple transmission optical fibers 5.

[0102] The fiber optic sensors applicable to this application are interferometric fiber optic sensors 3, including Mach-Zehnder interferometers (MZI), Michelson interferometers, Sagnac interferometers, and Fabry-Pérot interferometers (FPI). Here, an FPI strain gauge sensor is used as an example, and its structure is as follows: Figure 3 (b) Figure 3 As shown in (c), this structure consists of two ordinary single-mode optical fibers on the left and right, with a small cladding connecting fiber in the middle, thus forming an FPI interferometer. M1 is the reflecting surface formed by the first end face (left) of the single-mode fiber and air, and M2 is the reflecting surface formed by the second end face (right) of the single-mode fiber and air. Its reflected light intensity can be expressed by the following formula:

[0103]

[0104] Among them, I r E represents the intensity of reflected light. r E represents the amplitude of the reflected electric field. in Let represent the amplitude of the incident electric field; R1 represents the reflectivity of the reflecting surface formed by the end face of the incident single-mode fiber and air; R2 represents the reflectivity of the reflecting surface formed by the end face of the right-hand single-mode fiber and air; α represents the transmission loss coefficient; n represents the refractive index of air; λ represents the wavelength of the incident light. This represents the phase transition of a single-pass beam after passing through the FP cavity. The reflectance spectrum of this sensor is a periodic function, and its free spectral range (FSR) can be expressed as: For ease of calculation, λ is taken as 1550nm.

[0105] Based on preliminary measurements, such as Figure 3 (c) In the physical diagram of the interferometric strain fiber optic sensor, the actual nL of the interferometric strain fiber optic sensor is 102 μm, the FSR is 11.77 nm, and the strain sensitivity of the sensor is 0.005 nm / με.

[0106] A flowchart illustrating a method for amplifying the sensitivity of an interferometric fiber optic sensor is shown below. Figure 4 As shown, it is divided into a pre-operation section and an actual measurement section.

[0107] The pre-operation section is as follows:

[0108] The raw broadband light source spectral data of broadband light source 1 collected is denoted as O, such as... Figure 5 As shown in (a).

[0109] Virtual spectral data set P is generated according to the formula for calculating the reflected light intensity of FPI.

[0110] Let n′=1, such that L i The value varies from (10μm-400μm) with a step size of 0.5μm. Its amplitude is set to approximately 4dB. This yields 780 sets of virtual spectral data P, denoted as P1, P2, P3, P4, ..., P... 781 Spectral P i The corresponding value is n′L i =10+(i-1)*0.5μm, denoted as the preset numbering formula. P1 corresponds to the artificial spectrum with n′L1 of 10μm, P2 corresponds to the artificial spectrum with n′L2 of 10.5μm, and so on.

[0111] The original broadband light source spectral data O is multiplied by a base-10 exponentiation and then multiplied by the aforementioned virtual spectral data set P. The logarithm of each intermediate spectral data point in these multiplied intermediate spectral data sets is then taken again to obtain the artificial spectral data set O. i They are denoted as O1, O2, O3, ..., O 781 .like Figure 5 (b)- Figure 5 (d) shows several typical artificial spectral data, followed by... Figure 5 (b) is a schematic diagram of an artificial spectrum with a virtual cavity length parameter of 10 μm; Figure 5 (c) is a schematic diagram of an artificial spectrum with a virtual cavity length parameter of 105 μm; Figure 5 (d) shows an artificial spectrum with a virtual cavity length parameter of 400 μm. (Data acquired by a spectrometer is usually presented in logarithmic form. Taking the antilogarithm can convert the logarithmic data acquired by the spectrometer back to linear form, making subsequent data processing and analysis more consistent with the physical spectral characteristics.)

[0112] The above artificial spectral data groups O1, O2, O3, ..., O 781 Stored in the memory of spectrometer 4.

[0113] The method for achieving the vernier effect in the actual measurement section is as follows:

[0114] 1. For example Figure 3 The device is connected as shown in (a).

[0115] 2. Set channel A of spectrometer 3 to real-time scanning. At this time, the spectrum of channel A of spectrometer 3 is the measured spectral data S after the broadband light source 1 passes through the FPI.

[0116] 3. Set the desired preset target magnification m, and determine the required artificial spectral data sequence number x in the artificial spectral data set based on the desired preset target magnification, x∈{1,2,3,.....,I}. Calculate the required virtual cavity length n′L to be matched according to the following Vernier effect sensitivity formula. x Reference FPI.

[0117]

[0118] Where m represents the preset target magnification; FSR1 and FSR2 are the free spectral range of the acquired interferometric sensor and the free spectral range of the selected artificial spectrum, respectively; n′=1, representing the virtual refractive index corresponding to the virtual spectrum, L x This represents the target virtual cavity length parameter. All units used in the above formulas are in μm.

[0119] After rounding to a factor with a precision of 0.5 μm, and then setting n′L x Substitute into the numbering formula n′L x =10+(x-1)*0.5μm to calculate the index i in the artificial spectral data set that is equal to x. In the embodiment, the preset target magnification m is 30. Combined with the strain sensor FSR = 11.77nm in the embodiment, the required n′L is calculated according to the Vernier effect sensitivity amplification formula. x The value is 105.4 μm, so we choose 105.5 μm. Then, according to the preset numbering formula, the required sequence number x is 192. We select the artificial spectral data at i = x = 192 from the artificial spectral data group, i.e., O. 192 For the required artificial spectral data.

[0120] 4. Select the O corresponding to the above steps from the storage unit of spectrometer 4. x (e.g. O) 192 The spectrum is collected and stored in channel B, and channel B is then fixed (i.e., scanning is stopped). In this embodiment, O is selected. 192 It is then stored in channel B and fixed.

[0121] 5. Set channel C of spectrometer 4 to AB. The spectrum in channel C is now vernier effect spectral data, and the spectrum in channel C is acquired for demodulation. The acquired vernier effect spectral data set is denoted as V. For example... Figure 6 The image shown is one of the Vernier effect spectra from the C channel of the embodiment.

[0122] In summary, the principle behind the above operations is as follows:

[0123] The original broadband light source spectral data is O, which can be represented by the function O(λ).

[0124] The spectra in the virtual spectral data set P can be represented as:

[0125]

[0126] Where D1 is the spectrum P i The amplitude.

[0127] The data in channel A of the spectrometer can be represented as A(λ) = O i =lg(10) O(λ) *P i (λ)), this data is fixed once selected.

[0128] Similarly, channel B acquires the real-time spectrum of broadband light source 1 after passing through the FPI, which can be represented by a function. In this representation, D2 represents the intensity amplitude of the measured spectral data S of the broadband light source 1 after passing through the FPI, and the data in channel B can be expressed as B(λ) = lg(10) O(λ) *S(λ)).

[0129] If the spectrometer channel C = AB, then the spectral data of channel C can be expressed as:

[0130]

[0131] According to the Vernier effect theory, when two spectra have similar free spectra, the virtual free spectral range in channel A of the spectrometer is FSR2, and the free spectral range of channel B (an interferometric sensor) is FSR1. Adding, subtracting, multiplying, and dividing these two spectra will produce a Vernier effect spectrum. The free spectral range of the envelope of the Vernier effect spectrum is larger than the original two, resulting in higher spectral drift sensitivity. Tracking this envelope can amplify the sensitivity. Since the data in the spectrometer is in logarithmic form, subtracting the data from channel A and channel B is equivalent to dividing the spectrum. Existing methods for generating the Vernier effect all use optical devices to add the spectra together.

[0132] 6. Perform upper envelope fitting on all spectra of the vernier effect spectral data set V, and select the peak value of the envelope as the feature tracking point. Read the wavelength values ​​of these feature tracking points and demodulate the specific physical quantity with the previously calibrated wavelength value-physical quantity parameter table. For example... Figure 6 The red line shows a schematic diagram of the upper envelope fitting. For example... Figure 7 The strain measurement results of this embodiment show that the strain sensitivity reached 0.149 nm / με, which is 29.8 times higher than the sensitivity of the original sensor that did not use the method of this application, i.e., the amplification factor m = 29.8. This is basically consistent with the preset target amplification factor of 30, proving that the effect of this application is excellent.

[0133] In summary, this application has the following beneficial effects:

[0134] 1. This application effectively reduces costs and simplifies operation. While maintaining the same demodulation architecture as a single-interferometric sensor, this application achieves enhanced sensitivity under the Vernier effect, significantly reducing system complexity and cost. Compared to traditional Vernier sensing solutions, its innovation lies in: ① Hardware simplification: No need to construct a physical reference cavity and related optical path coupling devices (such as circulators, couplers, etc.), reducing the number of optical components; ② Process optimization: Eliminating the reference cavity fabrication stage (such as precision machining, calibration, etc.), improving system integration efficiency; ③ Cost-effectiveness: Directly reducing material and manufacturing costs by simplifying the optical structure and assembly process.

[0135] 2. This method effectively reduces the difficulty of optical path matching in the Vernier effect, achieving a high success rate and precise amplification control. To achieve the ideal amplification, traditional Vernier effect methods require closely matching the optical path ratios (FSRs) of the two interferometric sensors, which is difficult to achieve through fabrication methods due to their complexity and low success rate. However, the method in this application can achieve Vernier effect spectral matching by selecting a suitable spectrum from the spectrometer's memory as a reference spectrum, significantly reducing the matching difficulty.

[0136] 3. This application can effectively improve the detection limit. Since the spectrum collected in this application is the Vernier effect spectrum resulting from the interaction between the reference spectrum presented in the spectrometer and the sensor spectrum, the detection limit of this system is the same as that of the Vernier effect spectrum produced by two physical interferometers. However, the device of this application only requires one sensor while ensuring the detection limit.

[0137] In one exemplary embodiment, a computer device is provided, which may be a server or a terminal, and its internal structure diagram may be as follows. Figure 8As shown, this computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides the environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The database stores processing data such as spectral cavity length parameters. The I / O interfaces are used for information exchange between the processor and external devices. The communication interface is used for communication with external terminals via a network connection. When executed by the processor, the computer program implements a method for amplifying the sensitivity of an interferometric fiber optic sensor.

[0138] Those skilled in the art will understand that Figure 8 The structures shown are merely block diagrams of some structures related to the present application and do not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than shown in the figures, or combine certain components, or have different component arrangements. In an exemplary embodiment, a computer device is provided, including a memory and a processor. The memory stores a computer program, and the processor executes the computer program to implement the steps in the above-described method embodiments.

[0139] In one exemplary embodiment, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0140] In one exemplary embodiment, a computer program product is provided, including a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0141] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0142] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium, and when executed, it can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0143] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0144] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0145] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A method for amplifying the sensitivity of an interferometric fiber optic sensor, characterized in that, The method for amplifying the sensitivity of the interferometric fiber optic sensor includes: Acquire raw broadband light source spectral data; Based on the original broadband light source spectral data and the virtual spectral data set, an artificial spectral data set is constructed; the virtual spectral data set is generated by different virtual cavity length parameters in the Fabry-Perot interferometer sensor according to the reflection spectrum calculation formula of the Fabry-Perot interferometer sensor. The measurement spectral data of the broadband light source under the test environment is acquired in real time through the interferometric fiber optic sensor to obtain the measurement spectral data set, and the measurement spectral data set is stored in channel A of the spectrometer; Based on the preset target magnification and the free spectral range of the interferometric sensor, the corresponding artificial spectral data is selected from the artificial spectral data group and stored as reference spectral data in channel B of the spectrometer, and channel B of the spectrometer is fixed. Subtract each measured spectral data point in channel A of the spectrometer from the reference spectral data in channel B of the spectrometer to obtain the vernier effect spectral data point, and store it in channel C of the spectrometer. For each vernier effect spectral data in channel C of the spectrometer, an upper envelope fitting operation is performed to obtain multiple envelope curves; The peak point of each envelope curve is used as the feature tracking point, and the wavelength value corresponding to each feature tracking point is recorded. Based on the preset wavelength value-physical quantity parameter table, the wavelength values ​​of each feature tracking point are demodulated to obtain the predicted value of the physical quantity to be measured in the environment under test within the prediction time period, thereby realizing the function of sensitivity amplification; the physical quantity to be measured is the target detection physical quantity of the original interferometric sensor, including temperature and strain.

2. The method for amplifying the sensitivity of the interferometric fiber optic sensor according to claim 1, characterized in that, The virtual spectral data set is generated based on the reflectance spectrum calculation formula of the Fabry-Perot interferometer sensor, using different virtual cavity length parameters in the Fabry-Perot interferometer sensor. Specifically, it includes: The following formulas are used to obtain multiple virtual cavity length parameters: L i =L0+i×ΔL; Among them, L i Let L0 represent the i-th virtual cavity length parameter, i = {1, 2, 3, ..., I}, where I represents the total number of virtual cavities; L0 represents the initial cavity length parameter; and ΔL represents the preset cavity length interval. The virtual reflection spectrum corresponding to each virtual cavity length parameter is calculated using the following formula: Among them, P i (λ) represents the virtual reflection spectrum corresponding to the i-th virtual cavity length parameter; E r,i E represents the amplitude of the reflected electric field for the i-th virtual cavity length parameter; in,i R1 represents the incident electric field amplitude of the i-th virtual cavity length parameter; R2 represents the reflectivity of the first end face of the Fabry-Perot interferometer sensor; α represents the transmission loss coefficient; n′ represents the virtual refractive index corresponding to the virtual spectrum; and λ represents the wavelength of the incident light. Based on each virtual cavity length parameter and the corresponding virtual reflection spectrum, a virtual spectral data set is obtained.

3. The method for amplifying the sensitivity of the interferometric fiber optic sensor according to claim 1, characterized in that, Based on the original broadband light source spectral data and the virtual spectral data set, an artificial spectral data set is constructed, specifically including: The original broadband light source spectral data is subjected to an exponential calculation operation with a base of 10 using the following formula. The exponentially processed original broadband light source spectral data is then multiplied by each virtual spectral data in the virtual spectral data set to obtain the intermediate spectral data set. The i =(10 O(λ) *P i (l)); Among them, O i O(λ) represents the intermediate spectral data corresponding to the i-th virtual cavity length parameter; O(λ) represents the original broadband light source spectral data; P i (λ) represents the virtual reflection spectrum corresponding to the i-th virtual cavity length parameter; The artificial spectral data set is obtained by taking the logarithm of each intermediate spectral data set using the following formula. A i (λ)=lg(10 O(λ) *P i (l)); Among them, A i (λ) represents the artificial spectral data corresponding to the i-th virtual cavity length parameter.

4. The method for amplifying the sensitivity of the interferometric fiber optic sensor according to claim 1, characterized in that, Based on the preset target magnification and the free spectral range of the interferometric sensor, corresponding artificial spectral data are selected from the artificial spectral data set as reference spectral data, specifically including: Based on the preset target magnification and the free spectral range of the acquired interferometric fiber optic sensor, the corresponding target virtual cavity length parameter L is obtained using the vernier effect sensitivity amplification formula. x ; Based on the corresponding target virtual cavity length parameter L x The target virtual cavity length parameter L is calculated using a preset numbering formula. x The corresponding artificial spectral data number x to be selected; Based on the artificial spectral data number x to be selected, the corresponding artificial spectral data is selected from the artificial spectral data group.

5. The method for amplifying the sensitivity of the interferometric fiber optic sensor according to claim 4, characterized in that, The formula for vernier effect sensitivity is: Where m represents the preset target magnification; FSR1 and FSR2 are the free spectral ranges of the acquired interferometric sensor and the selected artificial spectrum, respectively; n′=1, representing the virtual refractive index corresponding to the virtual spectrum; L x Indicates the target virtual cavity length parameter; The default numbering formula is: n′L x =10+(x-1)*0.5μm; Where x represents the sequence number of the artificial spectral data to be selected, x∈{1,2,3,.....,I}.

6. The method for amplifying the sensitivity of an interferometric fiber optic sensor according to claim 2, characterized in that, The virtual cavity length parameter varies from 10μm to 400μm; the preset cavity length interval is 0.5μm.

7. A device for amplifying the sensitivity of an interferometric fiber optic sensor, characterized in that, The amplification device for the sensitivity of the interferometric fiber optic sensor uses the amplification method for the sensitivity of the interferometric fiber optic sensor as described in any one of claims 1-6, and the amplification device for the sensitivity of the interferometric fiber optic sensor comprises: Broadband light source, circulator, spectrometer, interferometric fiber optic sensor, multiple transmission fibers; The first port of the circulator is connected to a broadband light source via a transmission optical fiber, the second port of the circulator is connected to an interferometric fiber optic sensor via a transmission optical fiber, and the third port of the circulator is connected to the input end of a spectrometer via a transmission optical fiber. The broadband light source is used to transmit optical signals to the interferometric fiber optic sensor; The interferometric fiber optic sensor is used to receive the light signal emitted by the broadband light source and reflect it to obtain the measurement spectral data of the interferometric fiber optic sensor under the test environment, and transmit the measurement spectral data to the spectrometer. The spectrometer has data acquisition channels including channel A, channel B, and channel C. It is used to select corresponding artificial spectral data from the artificial spectral data set according to a preset target magnification, store this as reference spectral data in channel B of the spectrometer, and fix channel B. Each measured spectral data in the measured spectral data set in channel A of the spectrometer is subtracted from the reference spectral data in channel B to obtain a vernier effect spectral data set, which is then stored in channel C. An upper envelope fitting operation is performed on each vernier effect spectral data in the vernier effect spectral data set in channel C of the spectrometer to obtain multiple envelope curves. The peak point of each envelope curve is used as a feature tracking point, and the wavelength value corresponding to each feature tracking point is recorded. Based on a preset wavelength value-physical quantity parameter table, the wavelength value of each feature tracking point is demodulated to obtain the predicted value of the measured physical quantity in the environment under test within the prediction time period, thus achieving the function of sensitivity amplification. The measured physical quantity is the target physical quantity detected by the original interferometric sensor, including temperature and strain.

8. A computer device, comprising: A memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that the processor executes the computer program to implement a method for amplifying the sensitivity of the interferometric fiber optic sensor according to any one of claims 1-6.

9. A computer-readable storage medium having a computer program stored thereon, characterized in that, When executed by a processor, the computer program implements the method for amplifying the sensitivity of the interferometric fiber optic sensor as described in any one of claims 1-6.

10. A computer program product, comprising a computer program, characterized in that, When executed by a processor, the computer program implements the method for amplifying the sensitivity of the interferometric fiber optic sensor as described in any one of claims 1-6.

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